Spool valve



E'. B. LEAR SPOOL VALVE Filed .June 20 INVENTOR Ear/B Hi5 ATTORNE Patented Sept. 14, 1926.

UNITED STATES PATENT OFFICE.

EARL B. LEAR, OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR TO INGERSOLLTRAND COM- PANY, OF JERSEY CITY, NEW JERSEY, A GORPORATION ,OF NEW JERSEY.

SPOOL VALVE.

This invention relates to fluid actuated rock drills, but more particularly to a spool type fluid actuated distributing valve for rock drills of the hammer type.

. One object of the invention is to equip a rock drill witha valve so constructed as to prevent centering of said valve. Another object is to produce a valve of the spool type which is quick and sensitive in operation and efiicient in action.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention consists of the combinations of elements, features of construction and arrangement of parts having the general mode of operation substantially as hereinafter described and more particularly pointed out in the appended claims and illustrated in the accompanying drawin s.

T igure 1 is a longitudinal view in section of so much of a rock drill as will serve to illustrate the invention, and

Figure 2 is a view similar to Figure 1 showing the reciprocatory parts in a different position.

Referring to the drawings, the invention is shown embodied in a rock drill having a cylinder A in which is arranged a reciprooatory piston B for delivering blows upon a drill steel (not shown). A front cylinder washer C is disposed within the front end of the cylinder A and has a bore D to receive slidably a fluted forward extension E of the piston B, and also to form a closure for the front end of the cylinder. The back end of the cylinder A is sealed by a back cylinder washer F. The washer F s in this instance held against displacement b a rotation ratchet G and the eylinder The cylinder A, the back cylinder washer F, and the rotation ratchet Gr may be held in operative position by any suitable means, as for instance, side bolts (not shown) arrangedon opposite sides of these parts and which serve to clamp the said parts firmly in position.

Rotation of the piston is in this instance accomplished by means of a rifle bar H whichengages the piston in the usual manner. The rifle bar H is provided with a ratchet head J which carries spring actuated pawls K to cooperate with ratchet teeth L formed in the rotation ratchet G for mpa ing r y movement to he pison du g s orwa d stroke .A valve chest 0, which may be posi? tioned with respect to, the cylinder A as illustrated in the drawings, or in any other convenient position, is provided withabore P n whi h in th ins an e a bushing Q is arranged. Thebushing Q is provided with a bore B which forms a seat for a distributing valve S, The valve S this instance has a recess Sr. in constant com: munication with a passage preferably term d coax a ly with t e bor lt-andlead ms m a source f Pressu e fluid upply- A P f P U n V. (sh wn. in this i stance formed in one side of the bushing Q) communicates with the front and rear ends of the cylinder A through inlet passages W and X respectively.

In accordance with the practice of the invention, an enlarged bore Y forming a pressure chamber is formed in one end of the bushing to receive slidably a flange Z on one end of the valve S. A wall I at only one end of the valveforms actuating faces 0 and d for throwing the valve and for holding said valve ill thrown position.

A plurality of ports (2 are formed inthe walls of the valve and are adapted to register with the ports U and V for supplying pressure fluid to the front and rear ends of the cylinder respectively for actuating the. piston. In this instance, a small passage ffis formed in the wall Z) for constantly admitting pressure fluid from the interior of the valve into the pressure chamber Y for throwing the valve rearwardly to the position shown in Figure 2. A passage 9 leading from the pressure chamber Y communicates with the cylinder A at a point near the opening of the inlet passage X and is controlled by the piston B, An exhaust port it formed in the cylinder A provides a free exhaust for pres sure fluid from the ends of said cylinder and is controlled by the piston B,

Means are provided for preventing the forming of a cushion in the ends of the cylinder after the piston B closes the exhaust port h, and to this end a pair of cushion relief sorts j and 7c are formed in the valve chest and are so positioned with respect to the ports V. and U respectively that when the piston 13 closes the exhaust port h and approaches the end of its stroke, the atmospheric air in the cylinder is forced out through the inlet passage and through one or the other of said cushion relief ports j and 70, depending upon the direction in which the iston is moving. A vent 0 formed in tie bushing Q establishes communication between the chamber Y and the port to prevent the formation of the cushion between a shoulder 22 of said bush ing and the flange Z.

In the operation of the machine with the parts in the positions indicated in Figure 1, pressure fluid flowing through the passage T into the interior of the valve S passes through the ports 6 into the port U and thence through the inlet passage into the front end of the cylinder and drives the piston B towards the back end of the cylinder A. While the pressure fluid is flowing to the front end of the cylinder, a small portion of pressure fluid also passes through the passage f into the pressure chamber Y, and thence through the passage 9 into the rearward end of the cylinder and to atmosphere in the manner previously described. As the piston approaches the rearward end of its stroke, the passage 9 is covered by the piston at about the same time that the exhaust port it is uncovered to release the pressure fluid from the front end of the cylinder to atmosphere. When the passage 9 is covered by the piston as shown in Figure 2 pressure fluid continues to flow through the passage f into the pressure chamber Y, and since the face 0 is of larger area than the opposing 'face 65, the valve is thrown to its opposite position. In this way the ports e are placed in registry with the inlet passage X, to admit pressure fluid to the rearward end of the cylinder for driving the piston forwardly. At the time the piston uncovers the exhaust port it during the forward stroke, the pressure fluid in the chamber Y is released to the atmosphere and the valve is again thrown to the position shown in Figure 1, thus completing the cycle of operations.

I claim:-

1. In a fluid actuated rock drill, the combination of a cylinder having a free exhaust port, a reciprocatory hammer piston in the cylinder controlling said exhaust port, a valve chest having a valve chamber with an enlarged pressure chamber at one end, inlet passages leading from the valve chamber to the ends of the cylinder, a valve in said chamber and having a recess, said recess being in constant communication with a pressure fluid supply, ports in the valve adapted to register with the inlet passages for supplying pressure fluid to the cylinder, a flange and a wall at only one end of the valve and integral therewith, an actuating and holding face at one end of the wall against which pressure fluid may act for throwing the valve in one direction and for holding it in thrown position, a passage through said wall for admitting pressure fluid to act against the other end of the wall for throwing the valve in the opposite direction and to hold the valve in thrown position, and a passage leading from the pressure chamber to the cylinder for exhausting pressure fluid from said chamber.

2. In a fluid actuated rock drill, the combination of a cylinder with a reciprocatory hammer piston in the cylinder, a free exhaust port in the cylinder controlled only by the piston, a valve chest having a valve chamber open at one end with an enlarged pressure chamber at the other end, inlet passages leading from the valve chamber to the ends of the cylinder, a spool valve in said chamber and having a longitudinal recess, said recess being in constant communication with a pressure fluid supply, ports in the valve adapted to register with the inlet passages for supplying pressure fluid from the interior of the valve to the cylinder, a flange and a wall at one end of the valve and integral therewith, an actuating and holding face at the inner end of the wall against which pressure fluid may constantly act for throwing the valve in a forwardly direction and for holding it in thrown position, an actuating and holding face at the outer end of the wall and the flange against which pres sure fluid may act for throwing the valve in a rearwardly direction and for holding it in thrown position, a passage through said wall for constantly admitting pressure fluid to the pressure chamber for throwing the valve in a rearwardly direction, and a pas sage leading from the pressure chamber to the cyinlder for exhausting pressure fluid fron'i said chamber to permit the pressure fluid acting against the inner face of the wall to throw the valve in a forwardly direction, said passage being controlled by the piston.

in a fluid actuated rock drill, the combination of a cylinder with a. reoiprocatory hammer piston in the cylinder, a free exhaust port in the cylinder controlled only by the piston, a valve chest having a valve chamber with an enlarged pressure chamber at one end, inlet passages leading from the valve chamber to the ends of the cylinder, a spool valve in said chamber and having a longitudinal recess, said recess being in constant communication with a pressure fluid supply, ports in the valve adapted to register with the inlet passages for supplying pressure fluid trom the interior of the valve to the cylinder, :1, flange and a wall at only one end of the valve and integral therewith, an actuating-and holding face at the inner end of the wall against which pressure fluid may constantly act for throwing the valve in a forwardly direction and for holding it in thrown position, an actuating and holding face of larger diameter at the outer end of the wall and the flange against which pressure fluid may act for throwing the valve in a rearwardly direction and for holding it in thrown position, a passage through said wall constantly admitting pressure fluid to the pressure chamber to act against the outer actuating face for throwing the valve rearwardly, a passage leading from the pressure chamber to the cylinder for exhausting pressure fluid from said chamber to permit the pressure fluid acting against the inner actuating face to throw the valve in a forwardly direction, and passages leading from the valve chamber to the atmosphere adapted to communicate with the inlet passages for relieving compression from the ends of. the cylinder when the piston nears the end of its stroke, communication of said passages with the inlet passages being controlled only by the valve.

In testimony whereof I have signed this specification.

EAR-L B. LEAR. 

